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2.
Hum Reprod ; 2024 May 23.
Artículo en Inglés | MEDLINE | ID: mdl-38783613

RESUMEN

STUDY QUESTION: After an IVF cycle cancellation, does changing the stimulation protocol affect the odds of live birth and recurrent cancellation in the subsequent cycle? SUMMARY ANSWER: After IVF cycle cancellation, compared to those who repeated the same stimulation protocol, those who changed their protocol had higher odds of live birth and lower odds of recurrent cycle cancellation. WHAT IS KNOWN ALREADY: There is limited data addressing the effect of changing the stimulation protocol after an IVF cycle is cancelled during initial stimulation. The odds of live birth outcomes are not known so far in studies addressing the effect of changing the protocol. STUDY DESIGN, SIZE, DURATION: Retrospective Cohort Study using the 2014-2017 Society for Assisted Reproductive Technology Clinic Outcome Reporting System (SART CORS) database. PARTICIPANTS/MATERIALS, SETTING, METHODS: The data included 13 135 patients with a first autologous IVF cycle that resulted in a cycle cancellation and was followed by a second autologous cycle within the study period. We excluded fertility preservation cycles, supernumerary cycle attempts after the second IVF cycle attempt, and cycles with more than one stimulation protocol documented per cycle start. Patients who received the same protocol for both cycles (n = 6434) were compared to those who changed their protocol in the second cycle (n = 6701). Multivariable logistic regression analyses were performed to estimate the adjusted odds of live birth and recurrent cancellation. MAIN RESULTS AND THE ROLE OF CHANCE: Changing the protocol in the second cycle resulted 14% lower odds of recurrent cycle cancellation (P = 0.01) and 17% higher odds of live birth after fresh transfers (P = 0.04). When stratifying the data by specific combinations of protocol change (agonist flare, agonist suppression, antagonist), there was an increase in live birth when switching from antagonist to agonist suppression (odds ratio (OR) = 1.36, P = 0.03) and from agonist suppression to antagonist (OR = 1.73, P = 0.01) compared to those who repeated their same stimulation protocol. Specifically in poor responders, outcomes were worse when using the agonist flare protocol and significantly improved with the agonist suppression protocol. LIMITATIONS, REASONS FOR CAUTION: Comparison of response to stimulation between first and second cycles cannot be made in this study because the index IVF cycle was cancelled during ovarian stimulation, and thus there is no reportable outcome data for that cycle. Additionally, SART only tracks the three stimulation protocols addressed in this study and does not have data on more contemporary protocols that are used in poor responders thus limiting the generalizability of our findings. WIDER IMPLICATIONS OF THE FINDINGS: Using the SART CORS database, which includes >90% of all reported IVF cycles in the USA, provides generalizability to the demographically diverse IVF populations found here. In agreement with prior studies assessing change in IVF protocols, the agonist flare protocol seems to result in worse IVF outcomes, and based on our results, we believe that there is no role for the agonist flare protocol in patients with a prior poor response to stimulation. STUDY FUNDING/COMPETING INTEREST(S): None declared. TRIAL REGISTRATION NUMBER: N/A.

3.
BMC Cancer ; 16: 280, 2016 Apr 20.
Artículo en Inglés | MEDLINE | ID: mdl-27098543

RESUMEN

BACKGROUND: Few new compounds are available for relapsed osteosarcoma. We retrospectively evaluated the activity of gemcitabine (G) plus docetaxel (D) in patients with relapsed high-grade osteosarcoma and high-grade spindle cell sarcoma of bone (HGS). METHODS: Patients receiving G 900 mg/m(2) d 1, 8; D 75 mg/m(2) d 8, every 21 days were eligible. Primary end-point: progression-free survival (PFS) at 4 months; secondary end-point: overall survival (OS) and response rate. RESULTS: Fifty-one patients were included, with a median age of 17 years (8-71), 26 (51%) were pediatric patients. GD line of treatment: 2nd in 14 patients, ≥3rd in 37. 25 (49%) patients had metastases limited to lungs, 26 (51%) multiple sites. HISTOLOGY: 40 (78%) osteosarcoma, 11 (22%) HGS. Eight (16%) patients achieved surgical complete response (sCR2) after GD. Four-month PFS rate was 46%, and significantly better for patients with ECOG 0 (ECOG 0: 54% vs ECOG 1: 43% vs ECOG 2: 0%; p = 0.003), for patients undergoing metastasectomy after GD (sCR2 75% vs no-sCR2 40 %, p = 0.02) and for osteosarcoma (osteosarcoma 56% vs HGS 18%; p = 0.05), with no differences according to age, line of treatment, and pattern of metastases. Forty-six cases had RECIST measurable disease: 6 (13%) patients had a partial response (PR), 20 (43%) had stable disease (SD) and 20 (43%) had progressive disease (PD). The 1-year OS was 30%: 67% for PR, 54% for SD and 20% for PD (p = 0.005). CONCLUSIONS: GD is an active treatment for relapsed high-grade osteosarcoma, especially for ECOG 0 patients, and should be included in the therapeutic armamentarium of metastatic osteosarcoma.


Asunto(s)
Recurrencia Local de Neoplasia/tratamiento farmacológico , Osteosarcoma/tratamiento farmacológico , Sarcoma/tratamiento farmacológico , Adolescente , Adulto , Anciano , Niño , Desoxicitidina/administración & dosificación , Desoxicitidina/análogos & derivados , Supervivencia sin Enfermedad , Docetaxel , Femenino , Humanos , Estimación de Kaplan-Meier , Masculino , Persona de Mediana Edad , Clasificación del Tumor , Recurrencia Local de Neoplasia/patología , Osteosarcoma/patología , Recurrencia , Sarcoma/patología , Taxoides/administración & dosificación , Resultado del Tratamiento , Gemcitabina
4.
Disabil Rehabil Assist Technol ; 11(8): 683-94, 2016 11.
Artículo en Inglés | MEDLINE | ID: mdl-26218427

RESUMEN

PURPOSE: To describe the novel BrightArm Duo bimanual upper extremity (UE) rehabilitation system; to determine its technology acceptance and clinical benefit for older hemiplegic participants. METHODS: The system table tilted to adjust arm gravity loading. Participants wore arm supports that sensed grasp strength and wrist position on the table. Wrist weights further increased shoulder exertion. Games were designed to improve UE strength, motor function, cognition and emotive state and adapted automatically to each participant. The system underwent feasibility trials spanning 8 weeks in two skilled nursing facilities (SNFs). Participants were evaluated pre-therapy and post-therapy using standardized clinical measures. Computerized measures of supported arm reach, table tilt and number of arm repetitions were stored on a remote server. OUTCOMES: Seven participants had significant improvements in their active range of shoulder movement, supported arm reach, shoulder strength, grasp strength and their ability to focus. The group demonstrated higher arm function measured with FMA (p = 0.01) and CAHAI (p = 0.05), and had an improvement in depression (Becks Depression Inventory, II). BrightArm Duo technology was well accepted by participants with a rating of 4.4 out of 5 points. CONCLUSIONS: Given these findings, it will be beneficial to evaluate the BrightArm Duo application in SNF maintenance programs. Implications for Rehabilitation Integrative rehabilitation that addresses both physical and cognitive domains is promising for post-stroke maintenance in skilled nursing facilities. Simultaneous bilateral arm exercise may improve arm function in older hemiplegic patients several years after stroke. Virtual reality games that adapt to the patient can increase attention and working memory while decreasing depression in elderly.


Asunto(s)
Modalidades de Fisioterapia , Instituciones de Cuidados Especializados de Enfermería , Rehabilitación de Accidente Cerebrovascular/instrumentación , Rehabilitación de Accidente Cerebrovascular/métodos , Juegos de Video , Anciano , Anciano de 80 o más Años , Cognición , Depresión , Emociones , Femenino , Humanos , Masculino , Persona de Mediana Edad , Fuerza Muscular/fisiología , Rango del Movimiento Articular , Extremidad Superior/fisiología
5.
J Neonatal Perinatal Med ; 8(2): 113-8, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26410434

RESUMEN

BACKGROUND: The implications of early postnatal body weight changes (Δbw) in the morbidities related to body fluid metabolism in sick preterm infants in not well investigated. The extremely low birth weight infants (ELBW, birth weight <1000 g) have the highest incidence of such morbidities among all neonates. AIM: To determine the relationships between Δbw and neonatal morbidities associated with body fluid metabolism in the ELBW infants. METHODS: In an observational study, the associations between daily weight changes from birth weight (DΔ bw) and oxygen dependence on postnatal day 28 (BPD28), patent ductus arteriosus (PDA), intraventricular-periventricular hemorrhage (IVH), antenatal steroid (ANS) and gestational age (GA) were evaluated. Maximum weight loss (MΔ bw) was correlated with GA, BPD28 and BPD36 (oxygen dependence on postmenstrual 36 weeks). Pearson's correlation co-efficient and multivariate logistic regressions were performed for analysis. RESULTS: DΔ bw correlated inversely with GA on days 1-8 of life (p <  0.01 for all, 0.06 for DOL 2). DΔ bw was associated with a lower risk of BPD28 on days 6 (OR 0.87, 95% CI 0.76-1), 10 (OR 0.86, 95% CI 0.76-0.98) and 11 (OR 0.87, 95% CI 0.77-0.99); with PDA on days 8-11 (OR ranging between 0.89 to 0.92 for the 4 days, 95% CI 0.83 to 0.99) and with IVH on day 5 (OR 0.93, 95% CI 0.86-1) after controlling for GA. DΔ bw was not identified as risk factor for the tested morbidities. ANS decreased DΔ bw on days 4 (OR 0.88, 95% CI 0.78-1) and 10 (OR 0.9, 95% CI 0.84-1). MΔbw correlated directly with BPD28 (r = 0.3, p = 0.004), which declined after controlling for GA (r = 0.2, p = 0.2). CONCLUSIONS: DΔ bw is protective for PDA, BPD28 and IVH, independent of gestational age, whereas, the effects of MΔ bw on BPD are governed by maturation in ELBW infants. ANS decreases DΔbw, which correlates inversely with GA during the first week of life.


Asunto(s)
Displasia Broncopulmonar/etiología , Hemorragia Cerebral/etiología , Conducto Arterioso Permeable/etiología , Glucocorticoides/administración & dosificación , Displasia Broncopulmonar/mortalidad , Displasia Broncopulmonar/fisiopatología , Hemorragia Cerebral/mortalidad , Hemorragia Cerebral/fisiopatología , Conducto Arterioso Permeable/mortalidad , Conducto Arterioso Permeable/fisiopatología , Femenino , Humanos , Incidencia , Recien Nacido con Peso al Nacer Extremadamente Bajo , Recién Nacido , Recien Nacido Prematuro , Masculino , Pronóstico , Estudios Retrospectivos , Factores de Riesgo , Resultado del Tratamiento , Estados Unidos/epidemiología , Pérdida de Peso
7.
Phys Rev Lett ; 102(9): 090402, 2009 Mar 06.
Artículo en Inglés | MEDLINE | ID: mdl-19392500

RESUMEN

We use a Feshbach resonance to tune the scattering length a of a Bose-Einstein condensate of 7Li in the |F=1,mF=1> state. Using the spatial extent of the trapped condensate, we extract a over a range spanning 7 decades from small attractive interactions to extremely strong repulsive interactions. The shallow zero crossing in the wing of the Feshbach resonance enables the determination of a as small as 0.01 Bohr radii. Evidence of the weak anisotropic magnetic dipole interaction is obtained by comparison with different trap geometries for small a.

8.
Epidemiol Infect ; 137(10): 1396-404, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19296870

RESUMEN

Vitamin D has been shown to be an important immune system regulator. Vitamin D insufficiency during winter may cause increased susceptibility to upper respiratory tract infections (URIs). To determine whether vitamin D supplementation during the winter season prevents or decreases URI symptoms, 162 adults were randomized to receive 50 microg vitamin D3 (2000 IU) daily or matching placebo for 12 weeks. A bi-weekly questionnaire was used to record the incidence and severity of URI symptoms. There was no difference in the incidence of URIs between the vitamin D and placebo groups (48 URIs vs. 50 URIs, respectively, P=0.57). There was no difference in the duration or severity of URI symptoms between the vitamin D and placebo groups [5.4+/-4.8 days vs. 5.3+/-3.1 days, respectively, P=0.86 (95% CI for the difference in duration -1.8 to 2.1)]. The mean 25-hydroxyvitamin D level at baseline was similar in both groups (64.3+/-25.4 nmol/l in the vitamin D group; 63.0+/-25.8 nmol/l in the placebo group; n.s.). After 12 weeks, 25-hydroxyvitamin D levels increased significantly to 88.5+/-23.2 nmol/l in the vitamin D group, whereas there was no change in vitamin D levels in the placebo group. There was no benefit of vitamin D3 supplementation in decreasing the incidence or severity of symptomatic URIs during winter. Further studies are needed to determine the role of vitamin D in infection.


Asunto(s)
Colecalciferol/uso terapéutico , Infecciones del Sistema Respiratorio/prevención & control , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Colecalciferol/administración & dosificación , Femenino , Humanos , Masculino , Persona de Mediana Edad , Placebos/administración & dosificación , Encuestas y Cuestionarios , Adulto Joven
9.
J Physiol Pharmacol ; 60 Suppl 5: 81-6, 2009 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20134045

RESUMEN

Cigarette smoking (CS) is associated with a variety of human pathologies including cardiovascular disease and cancer. Human monocytes are prevalent in oral and respiratory mucosa and may be affected by exposure to CS, which induces oxidative stress. As a result, up-regulation of nuclear factor-kappaB (NF-kappaB) may occur. Our aims were to analyze a possible regulatory effect of CS on NF-kappaB activity in human monocytes. Human monocyte cell lines were exposed to CS in vitro. Our findings show that in vitro exposure to CS did not affect viability of human monocytes and was associated with increased production and secretion of IL-8 and up-regulation of certain C-C chemokines. Inhibition of NF-kappaB with curcumin or parthenolide resulted in a decrease of IL-8 secretion. CS also impaired the differentiation of monocytes. However, induced secretion of IL-8 from differentiated monocytes was not impaired. Our results indicate that exposure to CS stimulates pro-inflammatory activity of human monocytes through the activation of NF-kappaB pathway and also interferes with monocyte differentiation, which could play a role in the carcinogenic effects of cigarette smoking.


Asunto(s)
Diferenciación Celular/fisiología , Mediadores de Inflamación/metabolismo , Monocitos/patología , Nicotiana , Humo/efectos adversos , Fumar , Células Cultivadas , Curcumina/farmacología , Humanos , Mediadores de Inflamación/fisiología , Interleucina-8/metabolismo , Monocitos/metabolismo , Fumar/efectos adversos , Nicotiana/efectos adversos
10.
Phys Rev Lett ; 101(7): 071101, 2008 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-18764520

RESUMEN

Variations in the electrostatic surface potential between the proof mass and electrode housing in the space-based gravitational wave mission Laser Interferometer Space Antenna (LISA) is one of the largest contributors of noise at frequencies below a few mHz. Torsion balances provide an ideal test bed for investigating these effects in conditions emulative of LISA. Our apparatus consists of a Au coated Cu plate brought near a Au coated Si plate pendulum suspended from a thin W wire. We have measured a white noise level of 30 microV/sqrt Hz above approximately 0.1 mHz, rising at lower frequencies, for the surface potential variations between these two closely spaced metals.

11.
Osteoporos Int ; 19(7): 1001-9, 2008 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-18224269

RESUMEN

UNLABELLED: The remodeling transient describes a change in bone mass that lasts one remodeling cycle following an intervention that disturbs the calcium economy. We demonstrated the transient in a study of the response of bone density to calcium/vitamin D3 supplementation and show the hazards of misinterpretation if the transient is not considered. INTRODUCTION: The remodeling transient describes a change in bone mass that lasts for one remodeling cycle following an intervention that disturbs the calcium economy. METHODS: We report an intervention with calcium and vitamin D supplementation in 208 postmenopausal African-American women where the remodeling transient was considered a priori in the study design. Both groups (calcium alone vs. calcium + 20 microg (800 IU) vitamin D3) were ensured a calcium intake in excess of 1200 mg/day. RESULTS: There were no differences between the two groups in changes in BMD over time. These BMD changes were therefore interpreted to reflect increased calcium intake in both groups but not any influence of vitamin D. A transient increase in bone mineral density was observed during the first year of study, followed by a decline. The remodeling period was estimated at about 9 months, which is similar to histomorphometric estimates. CONCLUSION: It is problematic to draw conclusions concerning interventions that influence the calcium economy without considering the remodeling transient in study design. Studies of agents that effect bone remodeling must be carried out for at least two remodeling cycles and appropriate techniques must be used in data analysis.


Asunto(s)
Conservadores de la Densidad Ósea/farmacología , Densidad Ósea/efectos de los fármacos , Remodelación Ósea/fisiología , Calcio/farmacología , Colecalciferol/farmacología , Osteoporosis Posmenopáusica/tratamiento farmacológico , Absorciometría de Fotón , Negro o Afroamericano , Anciano , Biomarcadores/sangre , Densidad Ósea/fisiología , Calcio/sangre , Colecalciferol/sangre , Colágeno Tipo I/sangre , Femenino , Fémur/diagnóstico por imagen , Humanos , Persona de Mediana Edad , Osteocalcina/sangre , Osteoporosis Posmenopáusica/diagnóstico por imagen , Hormona Paratiroidea/sangre , Péptidos/sangre , Radio (Anatomía)/diagnóstico por imagen
12.
HIV Clin Trials ; 7(2): 70-85, 2006.
Artículo en Inglés | MEDLINE | ID: mdl-16798622

RESUMEN

BACKGROUND: ESPRIT, is a phase III, open-label, randomized, international clinical trial evaluating the effects of subcutaneous recombinant interleukin-2 (rIL-2) plus antiretroviral therapy (ART) versus ART alone on HIV-disease progression and death in HIV-1-infected individuals with CD4+ T-cells > or =300 cells/microL. OBJECTIVES: To describe the baseline characteristics of participants randomized to ESPRIT overall and by geographic location. METHOD: Baseline characteristics of randomized participants were summarized by region. RESULTS: 4,150 patients were enrolled in ESPRIT from 254 sites in 25 countries. 41%, 27%, 16%, 11%, and 5% were enrolled in Europe, North America, South America, Asia, and Australia, respectively. The median age was 40 years, 81% were men, and 76%, 11%, and 9% were Caucasian, Asian, and African American or African, respectively. 44% of women enrolled (n = 769) were enrolled in Thailand and Argentina. Overall, 55% and 38% of the cohort acquired HIV through male homosexual and heterosexual contact, respectively. 25% had a prior history of AIDS-defining illness; Pneumocystis jirovecii pneumonia, M. tuberculosis, and esophageal candida were most commonly reported. Median nadir and baseline CD4+ T-cell counts were 199 and 458 cells/muL, respectively. 6% and 13% were hepatitis B or C virus coinfected, respectively. Median duration of antiretroviral therapy (ART) was 4.2 years; the longest median duration was in Australia (5.2 years) and the shortest was in Asia (2.3 years). 17%, 13%, and 69% of participants began ART before 1995, between 1996 and 1997, and from 1998 onward, respectively. 86% used ART from two or more ART classes, with 49% using a protease inhibitor-based regimen and 46% using a nonnucleoside reverse transcriptase inhibitor-based regimen. 78% had plasma HIV RNA below detection (<500 cp/mL). CONCLUSION: ESPRIT has enrolled a diverse population of HIV-infected individuals including large populations of women and patients of African-American/African and Asian ethnicity often underrepresented in HIV research. As a consequence, the results of the study may have wide global applicability.


Asunto(s)
Fármacos Anti-VIH/uso terapéutico , Recolección de Datos/estadística & datos numéricos , Infecciones por VIH/tratamiento farmacológico , VIH-1 , Interleucina-2/análogos & derivados , Ensayos Clínicos Controlados Aleatorios como Asunto/estadística & datos numéricos , Adulto , Terapia Antirretroviral Altamente Activa , Etnicidad/estadística & datos numéricos , Femenino , Salud Global , Infecciones por VIH/complicaciones , Hepatitis B/complicaciones , Hepatitis C/complicaciones , Humanos , Inyecciones Subcutáneas , Interleucina-2/administración & dosificación , Interleucina-2/uso terapéutico , Masculino , Proteínas Recombinantes/administración & dosificación , Proteínas Recombinantes/uso terapéutico , Conducta Sexual/estadística & datos numéricos , Resultado del Tratamiento , Salud de la Mujer
13.
AJNR Am J Neuroradiol ; 27(5): 989-94, 2006 May.
Artículo en Inglés | MEDLINE | ID: mdl-16687529

RESUMEN

BACKGROUND AND PURPOSE: Vertebroplasty and kyphoplasty can be associated with significant radiation exposure to the operator. We compared the exposure levels to an operator performing vertebral fracture augmentation with vertebroplasty and kyphoplasty, to assess a cement injection and a monitoring technique designed to reduce this exposure. METHODS: A neuroradiologist performed 189 consecutive vertebral augmentation procedures in 135 patients with osteoporotic compression fractures by using a bilateral approach with biplane pulse fluoroscopy at 7.5 pulses/second. Cement delivery was performed with intermittent fluoroscopy with kyphoplasty and vertebroplasty by using syringes or continuous fluoroscopic monitoring with a cement delivery system (CDS). Data collection included time and operator exposure parameters. RESULTS: A total of 87 kyphoplasty procedures, 82 vertebroplasty procedures with a CDS (VP-CDS), and 20 vertebroplasty procedures with syringes (VP-S) were safely performed. Mean fluoroscopy time for device positioning was 4.3 minutes for each procedure type. Mean fluoroscopy time (minutes) for cement delivery was significantly different for the 3 procedure types; 2.1 for kyphoplasty, 3.7 for VP-CDS, and 1.5 for VP-S (P < .0001). Comparable mean radiation exposure rates (microsieverts/minute) were 0.8 for kyphoplasty, 1.1 for VP-CDS, and 0.3 for VP-S during device-positioning and 1.7 for kyphoplasty, 2.9 for VP-CDS, and 0.2 for VP-S during cement injection (P < .002). CONCLUSION: Use of the modified cement injection technique and intermittent fluoroscopy with kyphoplasty and vertebroplasty with syringes results in a significantly lower operator exposure rate compared with vertebroplasty with a CDS.


Asunto(s)
Fluoroscopía/efectos adversos , Exposición Profesional/prevención & control , Procedimientos Ortopédicos , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad
14.
Clin Exp Dermatol ; 31(3): 435-40, 2006 May.
Artículo en Inglés | MEDLINE | ID: mdl-16681595

RESUMEN

BACKGROUND: Prolidase deficiency is a complex disease characterized by various skin manifestations accompanied by mental retardation, facial dysmorphism and susceptibility to pyogenic infections. METHODS: We assessed a patient presenting a peculiar phenotype combining manifestations of prolidase deficiency with features typical of hyper-IgE syndrome. Mutation analysis was performed using direct PCR amplification and PCR restriction fragment length polymorphism analysis. RESULTS: We identified a novel homozygous recessive mutation in the PEPD gene, which was found to segregate in the family of the patient with the disease and was not found in a panel of DNA samples representative of all major Druze families living in northern Israel. DISCUSSION: Our results suggest that prolidase deficiency associated with hyper-IgE syndrome, a rare disorder, can be caused by mutations in PEPD.


Asunto(s)
Dipeptidasas/deficiencia , Dipeptidasas/genética , Síndrome de Job/enzimología , Mutación Missense , Adulto , Secuencia de Bases , Consanguinidad , Análisis Mutacional de ADN , Femenino , Homocigoto , Humanos , Masculino , Datos de Secuencia Molecular , Linaje , Polimorfismo de Longitud del Fragmento de Restricción
15.
Endocr Rev ; 27(4): 398-426, 2006 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-16543383

RESUMEN

Meiosis is a double-division process that is preceded by only one DNA replication event to produce haploid gametes. The defining event in meiosis is prophase I, during which chromosome pairs locate each other, become physically connected, and exchange genetic information. Although many aspects of this process have been elucidated in lower organisms, there has been scant information available until now about the process in mammals. Recent advances in genetic analysis, especially in mice and humans, have revealed many genes that play essential roles in meiosis in mammals. These include cell cycle-regulatory proteins that couple the exit from the premeiotic DNA synthesis to the progression through prophase I, the chromosome structural proteins involved in synapsis, and the repair and recombination proteins that process the recombination events. Failure to adequately repair the DNA damage caused by recombination triggers meiotic checkpoints that result in ablation of the germ cells by apoptosis. These analyses have revealed surprising sexual dimorphism in the requirements of different gene products and a much less stringent checkpoint regulation in females. This may provide an explanation for the 10-fold increase in meiotic errors in females compared with males. This review provides a comprehensive analysis of the use of genetic manipulation, particularly in mice, but also of the analysis of mutations in humans, to elucidate the mechanisms that are required for traverse through prophase I.


Asunto(s)
Proteínas de Ciclo Celular/fisiología , Emparejamiento Cromosómico/fisiología , Recombinación Genética/fisiología , Animales , Proteína BRCA1/genética , Proteína BRCA1/fisiología , Proteínas de Ciclo Celular/genética , Emparejamiento Cromosómico/genética , ADN Helicasas/genética , ADN Helicasas/fisiología , Reparación del ADN/fisiología , Trastornos por Deficiencias en la Reparación del ADN/genética , Trastornos por Deficiencias en la Reparación del ADN/fisiopatología , Humanos , Profase Meiótica I/genética , Profase Meiótica I/fisiología , Mutación
16.
Ann N Y Acad Sci ; 1006: 277-90, 2003 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-14976024

RESUMEN

For molecular electronics to become a viable technology the factors that control charge transport across a metal-molecule-metal junction need to be elucidated. We use an experimentally simple crossed-wire tunnel junction to interrogate how factors such as metal-molecule coupling, molecular structure, and the choice of metal electrode influence the current-voltage characteristics of a molecular junction.


Asunto(s)
Electroquímica/instrumentación , Electroquímica/métodos , Transporte de Electrón , Electrónica/instrumentación , Electrónica/métodos , Modelos Químicos , Modelos Moleculares , Simulación por Computador , Computadores Moleculares , Conductividad Eléctrica , Nanotecnología/instrumentación , Nanotecnología/métodos , Semiconductores
17.
Lung ; 180(4): 229-39, 2002.
Artículo en Inglés | MEDLINE | ID: mdl-12391513

RESUMEN

Granulocyte colony-stimulating factor (G-CSF) increases the concentration and activation of neutrophils in the peripheral blood and has been used to prevent late-onset infection in premature infants. However, if G-CSF also augmented the inflammatory response in the lung, the incidence and severity of acute and chronic lung injury might be expected to increase. Using a newborn piglet model of acute lung injury, we examined the effects of rhG-CSF (recombinant-metHuG-CSF) on lung injury. Thirty-three newborn piglets were studied as follows: 1). Unventilated controls; 2). normally ventilated (PaCO2 = 35-45 torr) with room air(RA) for 48 h; 3). normally ventilated with RA for 48 h and received rhG-CSF (10 mg/kg/dose IV) at 0, 12, 24, and 36 h; 4). hyperventilated (PaCO2 = 15-25 torr) with 100% O2 for 48 h; 5) hyperventilated with 100% O2 for 48 h and received rhG-CSF (10 mg/kg/dose IV) at 0, 12, 24 and 36 h. Complete blood counts and and differentials were performed at 0, 24, and 48 h. Animals were sacrificed at 48 h, lungs were removed en bloc, and bronchoalveolar lavage (BAL) was performed. Total blood white blood cells and neutrophil counts increased significantly over 48 h in animals who received rhG-CSF either with normoventilation (p <0.0001) or hyperventilation with 100% O2 (p <0.003), and did not change significantly in the other experimental groups. However, there were no significant differences in BAL total cell counts, neutrophil chemotaxis activity, total protein, or albumin concentrations among the groups. Despite significantly increasing peripheral neutrophil counts, rhG-CSF did not potentiate acute lung injury or inflammation. This suggests that prophylactic administration strategies using rhG-CSF to prevent sepsis in premature infants should not increase the risk for developing acute and chronic lung disease.


Asunto(s)
Factor Estimulante de Colonias de Granulocitos/farmacología , Hiperoxia/complicaciones , Hiperoxia/tratamiento farmacológico , Enfermedades Pulmonares/tratamiento farmacológico , Enfermedades Pulmonares/etiología , Lesión Pulmonar , Pulmón/irrigación sanguínea , Aire , Animales , Animales Recién Nacidos , Líquido del Lavado Bronquioalveolar/citología , Quimiotaxis de Leucocito/efectos de los fármacos , Modelos Animales de Enfermedad , Recuento de Leucocitos , Neutrófilos/efectos de los fármacos , Oxígeno/farmacología , Porcinos
18.
J Bone Joint Surg Am ; 83(10): 1514-23, 2001 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11679602

RESUMEN

BACKGROUND: Electrical stimulation is used to treat nonunions and to augment spinal fusions. We studied the biochemical pathways that are activated in signal transduction when various types of electrical stimulation are applied to bone cells. METHODS: Cultured MC3T3-E1 bone cells were exposed to capacitive coupling, inductive coupling, or combined electromagnetic fields at appropriate field strengths for thirty minutes and for two, six, and twenty-four hours. The DNA content of each dish was determined. Other cultures of MC3T3-E1 bone cells were exposed to capacitive coupling, inductive coupling, or combined electromagnetic fields for two hours in the presence of various inhibitors of signal transduction, with or without electrical stimulation, and the DNA content of each dish was determined. RESULTS: All three signals produced a significant increase in DNA content per dish compared with that in the controls at all time-points (p < 0.05), but only exposure to capacitive coupling resulted in a significant, ever-increasing DNA production at each time-period beyond thirty minutes. The use of specific metabolic inhibitors indicated that, with capacitive coupling, signal transduction was by means of influx of Ca(2+) through voltage-gated calcium channels leading to an increase in cytosolic Ca(2+) (blocked by verapamil), cytoskeletal calmodulin (blocked by W-7), and prostaglandin E2 (blocked by indomethacin). With inductive coupling and combined electromagnetic fields, signal transduction was by means of intracellular release of Ca(2+) leading to an increase in cytosolic Ca(2+) (blocked by TMB-8) and an increase in activated cytoskeletal calmodulin (blocked by W-7). CONCLUSIONS: The initial events in signal transduction were found to be different when capacitive coupling was compared with inductive coupling and with combined electromagnetic fields; the initial event with capacitive coupling is Ca(2+) ion translocation through cell-membrane voltage-gated calcium channels, whereas the initial event with inductive coupling and with combined electromagnetic fields is the release of Ca(2+) from intracellular stores. The final pathway, however, is the same for all three signals-that is, there is an increase in cytosolic Ca(2+) and an increase in activated cytoskeletal calmodulin.


Asunto(s)
Osteoblastos/fisiología , Transducción de Señal , Animales , División Celular , Células Cultivadas , Estimulación Eléctrica , Ratones , Osteoblastos/citología , Transducción de Señal/efectos de los fármacos
20.
Pediatr Clin North Am ; 48(5): 1267-89, 2001 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11579674

RESUMEN

Thousands of adolescents are employed and routinely incur occupational exposures as part of their work. Case reports of adolescent exposure-related fatalities and illness, coupled with observational studies of chemical and other exposures with potential health risks, create a strong case for better tracking of work-related exposures and illness, better training for all working adolescents, education of their parents about risks, more clinical involvement in the health and safety of working adolescents, and advocacy for safer adolescent work environments. Because adolescents are neither children nor adults, much research is needed to clarify exposure patterns and risks; however, existing data on adolescent occupational injury and knowledge of exposures to adults in similar work environments permit immediate interventions. The most applicable information from the growing knowledge of environmental health in young children also can be borrowed and applied, especially to younger workers, such as those on farms, who may be children rather than adolescents. Crucial to future protection of working youth from occupational exposures are application of knowledge that already is possessed about occupational risks to adults, a cultural change in the way the US population views risks of chemical exposures, and improved occupational health and safety protection for all adult workers. Improving occupational health for working adolescents may be more politically acceptable and thus feasible than starting with adults, but ultimately the two are linked inextricably. These are new realms for pediatricians, but pediatrician input is needed greatly on all of these levels.


Asunto(s)
Exposición a Riesgos Ambientales/efectos adversos , Exposición Profesional/efectos adversos , Características de la Residencia , Adolescente , Adulto , Niño , Preescolar , Exposición a Riesgos Ambientales/legislación & jurisprudencia , Salud Ambiental/legislación & jurisprudencia , Humanos , Masculino , Exposición Profesional/legislación & jurisprudencia
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